You can log back into your return and go though that section or open your return if you used the Desktop program. If you have already filed then scroll down and click on ADD A STATE to open the archived return.
THEN:
You can just type W4 in the search box at the top of your return , click on Find. Then Click on Jump To and it will take you to the estimated tax payments section. Say no to changing your W-4 and the next screen will start the estimated taxes section.
OR
Go to Federal Taxes or Personal (H&B version)
Other Tax Situations
Other Tax Forms
Form W-4 and Estimated Taxes - Click the Start or Update button